Biomechanics of cross-sectional size and shape in the hominoid mandibular corpus
Article first published online: 27 APR 2005
Copyright © 1989 Wiley-Liss, Inc., A Wiley Company
American Journal of Physical Anthropology
Volume 80, Issue 1, pages 91–106, September 1989
How to Cite
Daegling, D. J. (1989), Biomechanics of cross-sectional size and shape in the hominoid mandibular corpus. Am. J. Phys. Anthropol., 80: 91–106. doi: 10.1002/ajpa.1330800111
- Issue published online: 27 APR 2005
- Article first published online: 27 APR 2005
- Manuscript Accepted: 4 NOV 1988
- Manuscript Received: 14 JUN 1988
- Sigma Xi Foundation
- Computed tomography;
Mandibular cross sections of Pan, Pongo, Gorilla, Homo, and two fossil specimens of Paranthropus were examined by computed tomography (CT) to determine the biomechanical properties of the hominoid mandibular corpus. Images obtained by CT reveal that while the fossil hominids do not differ significantly from extant hominoids in the relative contribution of compact bone to total subperiosteal area, the shape of the Paranthropus corpora indicates that the mechanical design of the robust australopithecine mandible is fundamentally distinct from that of modern hominoids in terms of its ability to resist transverse bending and torsion. It is also apparent that, among the modern hominoids, interspecific and sexual differences in corpus shape are not significant from a biomechanical perspective.
While ellipse models have been used previously to describe the size, shape, and subsequent biomechanical properties of the corpus, the present study shows that such models do not predict the biomechanical properties of corpus cross-sectional geometry in an accurate or reliable manner.
The traditional “robusticity” index of the mandibular corpus is of limited utility for biomechanical interpretations. The relationship of compact bone distribution in the corpus to dimensions such as mandibular length and arch width may provide a more functionally meaningful definition of mandibular robusticity.